Long-Term Outcomes With Pembrolizumab Plus Chemoradiotherapy in Urothelial Bladder Cancer

By: Kayci Reyer
Posted: Monday, July 24, 2023

Updated follow-up efficacy and safety findings from a phase II trial presented at the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting (Abstract 4509) suggested that some patients with muscle-invasive urothelial bladder cancer may benefit from the addition of pembrolizumab to trimodality therapy. The study analyzed the effects of pembrolizumab, an immune checkpoint inhibitor, administered in conjunction with transurethral resection of the bladder tumor, hypofractionated radiotherapy, and biweekly gemcitabine chemotherapy.

“[Trimodality therapy] combined with [pembrolizumab] was well tolerated and continues to show promising early outcomes data,” concluded Minas P. Economides, MD, of New York University, and colleagues.

The multicenter study included 54 patients who enrolled between May 2016 and June 2022. Patients received 200 mg of intravenous pembrolizumab before undergoing maximal transurethral resection of the bladder tumor. This was followed by whole-bladder radiotherapy combined with 27 mg/m² of biweekly gemcitabine plus pembrolizumab every 3 weeks for a total of three treatments.

Overall, 46 patients completed all treatments. Most of the one (2%), three (6%), and four (7%) patients who discontinued radiotherapy plus gemcitabine, gemcitabine, or pembrolizumab, respectively, did so because of toxicity. At a median follow-up of 23 months, 12 patients experienced tumor recurrence, 4 of whom had non–muscle-invasive tumors. Of the 10 deaths (18%) that occurred during the study, 6 were from unknown causes, 3 were from disease progression, and 1 was from treatment toxicity. Grade 3 or higher adverse events were reported in 13 patients (24%), and grade 3 or higher immune-related adverse events occurred in 4 patients.

“A large phase III trial is underway to further explore this treatment,” noted the authors.

Disclosure: Dr. Economides reported no conflicts of interest. For full disclosures of the other study authors, visit coi.asco.org.

2023 ASCO Annual Meeting